Add thread-per-core setting to SkThreadPool.

BUG=
R=scroggo@google.com, caryclark@google.com

Author: mtklein@google.com

Review URL: https://chromiumcodereview.appspot.com/13855009

git-svn-id: http://skia.googlecode.com/svn/trunk@8802 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed